As is known, the current trend in the design of battery operated electronic equipment is to provide enhanced performance in smaller packages, while consuming less power. Accordingly, the components comprising the electronic equipment must provide enhanced performance in smaller packages, while consuming less power. As such, designers of electronic equipment and the corresponding components have created a multitude of power saving techniques. Such techniques, however, are usually specific to a particular set of operating conditions that include supply voltage, desired performance level, and usage. For example, when a component or circuit within the electronic equipment is intermittently used, a power regulation circuit disables the component or circuit during times when it is not in use. When the component is enabled, it draws the power it needs to operate.
As is also known, many types of battery operated electronic equipment may also be externally powered (e.g., by a power supply) or may have externally powered equivalents. Such powered devices typically include similar functionality and, hence, include similar components. Components for externally powered devices, however, have less stringent power consumption requirements and typically do not employ power conservation techniques. Components of battery operated electronic equipment that may also be powered by an external source may have different power consumption requirements depending on whether the electronic equipment is being powered by a battery or an external source. Typically, components function better when supplied with more power. For example, an amplifier has lower offset and greater drive capability when supplied with greater power.
As such, the component manufacturer may make several versions of the same component, one for each of the various operating conditions and types of power sources. For integrated circuits, this requires separate mask sets, packaging, and testing, which adds to the overall cost of the component. Therefore, a need exists for an adjustable power control circuit that is adjustable based on operating conditions and the types of power sources.